With the House sliced and diced into districts that leave most incumbents insulated from any serious reelection challenge — and a host of prized Senate recruits from both parties deciding they’d rather just stay home — control of Congress could be decided next year by the fewest number of states and congressional districts in a decade or more.

The parties out of power are in a critical window over the next several months to expand the map or risk ceding seats that should be within reach. They’re confident they’ll pull it off: Check back in the new year and the landscape will look a lot different, they say.

But at this point, the high-stakes fight for so few competitive seats means candidates in targeted races can look forward to 16 months of microscopic scrutiny and a flood of attack ads leading up to Election Day.

“It changes the whole situation,” said Guy Harrison, a former National Republican Congressional Committee executive director. “For those people caught in that crossfire, it’s an entirely new experience.”

A smaller playing field is typically easier for the party in power to defend, which should be good news for House Republicans and Senate Democrats. But the landscape on each side is not level.

House Republicans are strongly favored to remain in power, absent some jolt that triggers a voter revolt against Speaker John Boehner and his rowdy GOP conference. Some handicappers see the party actually increasing its 17-seat majority.

The Senate will take a lot less to flip: The handful of states expected to determine control of the chamber features electorates that favor the GOP, as well as a history of electing Republicans to statewide office. To return to the majority, the GOP needs to turn six Democratic seats red.

The Cook Political Report currently rates 66 House races as competitive, the smallest number at this point in an election cycle since 2004. In 2012, about 75 seats were considered to be in play, and in 2010 there were around 100 targeted contests.

On the Senate side, Cook ranks no contests as tossups. It considers only two seats now controlled by Democrats, in West Virginia and Montana, as “leaning” Republican — and no GOP-held seats as favoring Democrats. Though several other states are still very much in play, it’s the least competitive landscape at this point in the election cycle that the respected handicapper has found in 20 years.

“It’s almost like a presidential map with the battlegrounds,” said a Democratic strategist involved in the fight. “You’ll see the races start earlier. You’ll see a lot of activity in those states. It’s going to be a very focused cycle. In 2012, the map was just so open.”

The main reason for the shrunken battlefield is the failure of both parties to land prized recruits. Time and again, top-tier potential candidates have decided the lure of the Senate isn’t strong enough to endure a grueling campaign that might or might not end well.

Former Democratic Gov. Brian Schweitzer, the party’s best hope of keeping Sen. Max Baucus’s seat in their column, was only the latest example when he opted on July 13 not to run. Democrats haven’t turned up strong candidates in two states where members of their party are retiring, West Virginia or South Dakota, making them likely GOP pickups.

Republicans have had their own recruitment shortcomings. The party has yet to field quality candidates in purple and blue states that, if history and demographics are any guide, should be competitive.

The GOP also has yet to capitalize on Democratic retirements in Iowa and Michigan. The Democratic candidates, Reps. Bruce Braley of Iowa and Gary Peters of Michigan, have already cleared the field, while the GOP’s best options, Reps. Tom Latham and Mike Rogers, opted against running.

The GOP’s chances at this point rest on defeating three of four Democratic incumbents in states carried by Mitt Romney: Arkansas’ Mark Pryor, Alaska’s Mark Begich, Louisiana’s Mary Landrieu and North Carolina’s Kay Hagan.

Democratic operatives see the foursome as their firewall. They note that only three Democratic incumbents have lost in the past decade.

“Republican inability to expand the map has resulted in this small map that forces them to basically sweep incumbents,” said Democratic Senatorial Campaign Committee deputy executive director Matt Canter.

Neither side is contending the field will remain static; there’s plenty of time for quality candidates to emerge and put in play states that look relatively safe now, they say. Look no further than Sens. Ron Johnson (R-Wis.) and Heidi Heitkamp (D-N.D.), who both launched their campaigns late and were largely written off at first, to see how the map can expand in unexpected ways.

Republicans intend to play hard in Iowa and Michigan. They also promise to play in purple states like Colorado, Minnesota and New Hampshire. And they express confidence they can field competitive candidates in blue states like Hawaii, Oregon and Massachusetts.

“Democrat incumbents are going to be stunned this winter after realizing that they are going to face tough challenges in states that they have no idea are coming,” said National Republican Senatorial Committee communications director Brad Dayspring.

Democrats point to Kentucky and Georgia as two GOP-leaning states that they plan to make more competitive than they look today. They think they have Senate Minority Leader Mitch McConnell on the ropes, but their candidate in the Bluegrass State, Allison Lundergan Grimes, is seen as unlikely to ultimately take out the minority leader.

On the House side, Democrats and Republicans disagree about the exact size of the 2014 playing field. But there is a general consensus among strategists that between 50 and 75 seats are in play. Democrats need to pick up 17 seats to win the majority. That means that even if Democrats were to retain all 38 of their seats that are listed as vulnerable by Cook, they would need to win at least 17 of the 28 competitive Republican seats.

Candidates in the targeted races are gearing up early.

California Republican Carl DeMaio, who’s looking to unseat Democratic Rep. Scott Peters in a swing San Diego-area district, said he’s in heavy ramp-up mode, in anticipation of a costly contest that will see loads of cash from outside groups.

“One of the things you can never get back in a campaign is time,” he said. “We’re working hard right now, as if the election is tomorrow.”

The NRCC has already begun holding regular conference calls with GOP candidates, something it usually doesn’t do until much later in the election season. And Congressional Leadership Fund, a Republican super PAC, says it’s considering making an early investment in digital ads. One Democratic group, House Majority PAC, has already purchased nearly $200,000 in TV ads to batter a trio of vulnerable House Republicans on immigration reform.

House Democrats are working to expand the battlefield. They expect an increasing number of Republicans will find themselves in tough races as voters sour on a dysfunctional Congress. And they’re courting conservative-minded recruits to run in red districts. The Democratic Congressional Campaign Committee, for example, has begun to promote the candidacy of Jennifer Garrison, a former majority leader in the Ohio House of Representatives who opposes abortion.

“There are enough districts that are winnable for us, and it is our charge to recruit candidates and to hold Republicans accountable and put those races in play,” said DCCC executive director Kelly Ward. “We feel there’s enough turf to do that in that we’re not starting off with a tightened battlefield in any sense.”

The political atmosphere, basically neutral right now, could also shift dramatically. Wave elections in 2006, 2008 and 2010 made races competitive that few foresaw at this stage.

Republican consultant Mike Slanker was NRSC political director in 2008 when the incumbents up in 2014 won their seats at the peak of Obama’s popularity. The party had gone from hoping to play offense in states like Colorado to defending Mississippi.

Sen. Al Franken (D-Minn.) prevailed only after a long recount battle. Sen. Mark Begich (D-Alaska) won by only a few thousand votes after incumbent Ted Stevens was convicted of several felonies just before the election (the convictions were later voided over prosecutorial misconduct). Obama tailwinds got several others across the finish line. Many of these freshmen do not face top-tier challengers yet, but they might find themselves in tough races if that changes.

“You don’t know what’s going to happen with these guys who have never had to run in a tough environment,” said Slanker. “You’ve got to kick the tires … and see what they’re really made of.”